It depends how the bond market reacts. If the bond market reacts very badly the government will have to react if bond yields start to go up too much, he said. Zahn suggested that it would be unsustainable if the yield, or interest rate, on either 10-year or 30-year UK bonds reached 6%. Such high interest rates created a death spiral, he warned, meaning the government would hopefully act before yields rose that high.
I worry about complacency. Fiscal room for manoeuvre is thin across the developed world, and the toolkit that helped during the financial crisis-large‑scale QE, in particular-can't be mobilised in the same way again. Yields have risen sharply but mostly in an orderly fashion; we've not had many "cliff‑edge" moments outside Japan. That doesn't mean we're safe. If market participants decide they will only finance governments at much higher rates, the spiral can be vicious. We're vulnerable to that kind of shift in sentiment.
